Bis(perfluoromethylphenyl) cyanoalkylphosphates and bis(cyanoalkyl)perfluoromethylphenyl phosphates



Dec. 19, 1967 E BLAKE ET AL 3,359,349

BISPERFLUOROMETHYLPHENYL) CYANOALKYL PHOSPHATES AND BI5(CYANOALKYL) PERFLUOROMETHYLPHENYL PHOSPHATES Filed Oct. 9, 1964 FIGURE I FORCE 2 Y FIGURE 2 I' L I I 24 INVENTORS. EDWARD S. BLAKE RALPH E. De.BRUNNER BY JAMES A. WEBSTER ATTORNEY United States Patent 3,359,349 BIS(PERFLUOROMETHYLPHENYL) CYANOALKYL PHOSPHATES AND BIS(CYANOALKYL)PERF1LU- OROMETHYLPHENYL PHOSPHATES Edward S. Blake, Ralph E. De Brunner, and James A. Webster, Dayton, Ohio, assignors to Monsanto Research Corporation, St. Louis, Mo., a corporation of Delaware Filed Oct. 9, 1964, Ser. No. 402,836 Claims. (Cl. 260-940) wherein each of m and n is 1 or 2 and the sum of mi-f-n is 3, X is halogen having an atomic weight greater than 34, and alk denotes a bivalent alkylene radical of from 2 to 4 carbon atoms.

Depending upon whether there is employed a phosphoromonohalidate or a phosphorodihalidate the products are either bis(perfluoromethylphenyl) cyanoalkyl phosphates or bis(cyanoalkyl) perfluoromethylphenyl phosphates.

Phosphorohalidates which are useful for the present purpose include e.g., o-, mor p-perfluoromethylphenyl phosphorodichloridate or phosphorodib-romidate or phosphorodiiodidate, and bis(o-, mor p-perfiuoromethylphenyl) phosphorochloridate, or phosphorobromidate, or phosphoriodidate. The useful alkylene cyanohydrins inelude hydracrylonitrile, lactonitrile, 4-hydroxybutyronitrile, and S-hydroxyvaleronitrile. Thus bis(o-, mor pperfiuoromethylphenyl) phosphorochloridate or phosphorobromidate reacts with hydracrylonitrile to give bis(o-, mor p-perfluoromethylphenyl) 2-cyanoalkyl phosphate; bis(o-, mor p-perfluoromethylphenyl) phosphorochloridate or phosphoriodidate reacts with lactonitrile to give bis(o-, mor p-perfluoromethylphenyl) leyanoethyl phosphate; bis(o-, mor p-perfluoromethylphenyl) phosphorochloridate or phosphorobromidate reacts with S-hydroxyvaleronitrile to give bis(o-, mor pperfiuoromethylphenyl) 4-cyanobutyl phosphate, bis(o-, mor p-perfluoromethylphenyl) phosphorochloridate or phosphorobromidate reacts with 4-hydroxybutyronitrile to give bis(o-, mor p-perfluoromethyl) phenyl 3-cyanopropyl phosphate, etc.

o-, mor p-perfluoromethylphenyl phosphorodichloridate or phosphorodibromidate or phosphorodiiodidate reacts with hydracrylonitrile to give bis(Z-cyanoethyl) 0-, mor p-perfluoromethylphenyl phosphate, or with lactonitrile to give bis(l-cyanoethyl) o-, mor p-perfluoromethylphenyl phosphate, or with 4-hydroxybutyronitrile to give bis(S-cyanopropyl) o-, mor p-perfiuoromethylphenyl phosphate, or with S-hydroxyvaleronitrile to give bis(4-cyanobutyl) o-, mor p-perfluoromethylphenyl phosphate, etc.

Reaction of the phosphorohalidate or the phosphorodihalidate with the alkylene cyanohydrin takes place by simply contacting the halogen compound with the cyanohyd-rin at ambient temperature or with heating. In some instances, reaction rate is accelerated by heating; and, particularly when working with the higher molecular Weight cyanohydrins, temperatures of from, say, 50 C. to below the decomposition temperature of either the reactants or the ester product are employed. Generally, depending upon the nature of the individual reactants, temperatures of from, say, 0 C. to 150 C. and preferably of from, about 0 C. to C. are useful.

The reaction may or may not be conducted in the presence of an inert, organic liquid diluent or solvent, e.g., a halogenated alkane such as chloroform, carbon tetrachloride or ethylene chloride; an ether such as ethyl ether, dioxane, diethylene glycol dimethyl ether; an amide such as dimethylformamide or dimethylacetamide.

A catalyst may or may not be used. Operation in the presence of a basic agent is recommended, since the latter serves as scavenger for the by-produet hydrogen halide. The basic agent may be inorganic or organic, e.g., it may be a tertiary alkylamine such as triethylamine or tributylamine; a heterocyclic nitrogen base such as N-methyl- 'morpholine or pyridine; an alkali or alkaline earth metal oxide or the basic salt thereof such as sodium, potassium, lithium, calcium or magnesium oxide, carbonate or acetate, etc.

All of the reaction conditions, i.e., whether or not a diluent and/or a basic agent is employed and the nature of the diluent or of said agent if it is used, temperature, pressure, reaction time, reactant proportions, etc., can be readily arrived at by easy experimentation. Thus, arrival at optimum reaction conditions is simply a matter of routine procedure by one skilled in the art. Reaction is generally rapid and is usually evidenced by evolution of hydrogen halide if no scavenger is used. When an organic amine is employed as scavenger, reaction is frequently evidenced by copious precipitation of the amine hydrohalide. To assure complete reaction in experimental runs, it is generally recommended that after initial reaction has appeared to subside, the reaction mixture be allowed to stand at room temperature for a time before working up the product or that the temperature of the reaction mixture be increased to assure complete reaction.

As has already been pointed out, formation of the presently provided bis(perfluoromethylphenyl) cyanoalkyl phosphates takes place by condensation of one mole of the bis(perfluoromethylphenyl) phosphorohalidate with one mole of the appropriate cyanohydrin; Whereas, formation of the bis(cyanoalkyl) perfluoromethyl phosphates takes place by condensation of one mole of the perfluoromethylphenyl phosphorodihalidate with two moles of the cyanohydrin. Hence, the reactants are advantageously employed in such stoichiometric proportions. However, an excess of the cyanohydrin may be employed, and such excess is recommended when it is desired to assure complete reaction of the more diflicultly available halogen-containing reactant. Any excess of the 9 .J reactant may be readily recovered from the final reaction mixture, e.g by vacuum distillation. When a basic scavenger is used, the resulting hydrohalide is readily removed from the reaction product by filtering or centrifuging, since it is insoluble in most organic solvents and in the reactants.

The presently provided cyanoalkyl perfluoromethyltions. They possess good viscosity/ temperature relationships and are also useful, e.g., as heat-exchange media, gyro fluids, and lubricants.

Evaluation of the hydraulic fluid eflicacy of the presently provided cyanoalkyl perfluoromethylphenyl phosphates was conducted by determining such characteristics as pour point, kinematic viscosity, autogenous ignition temperature and behavior upon sudden exposure to very high temperatures. The following procedures were used to obtain the data given in the following examples.

The pour point was determined by American Society for Testing Materials (hereinafter referred to as ASTM) procedure D9757, except that a small pour point tube, Model F2436 supplied by Scientific Glass Apparatus Company was substituted for the larger tube prescribed in said ASTM procedure. This was done to conserve test material.

Kinematic viscosity was determined by ASTM D445-T 1961 procedure, using Cannon-Manning Semi-Micro viscometers, calibrated and supplied by the Scientific Development Corporation, State College, Pennsylvania.

The autogeous ignition temperature Was determined by ASTM D2l55-60T procedure.

Flammability at 1300 F. was determined by visual observation of the behavior of the test material when introduced dropwise at the surface of molten aluminum which is maintained at 1300" F. If no burning resulted, a single spark was applied for a more stringent test of fire resistance Fluidpaint compatibility was evaluated as follows: A 4" by 12" sheet of a mild steel was sandblasted to a satin finish using ZOO-mesh aluminia. A surface thereof was then coated, using a doctor blade, with a 2 mil wet thickness of a standard alkyl base primer. The coated sheet was dried for 24 hours at 80 F. and 50% relative humidity and a second coat of a standard alkyd base finish was similarly applied and dried on top of the first coat. Four portions (ca. 0.05 ml. each) of the test fluid were placed on the dried finish, covered by watch glasses, and kept at ambient temperature. The effect of the fluid on the finish upon which it had been placed was visually observed after 24 hours.

Owing to the excellent physical properties of the present cyanoalkyl perfluoromethylphenyl phosphates, the invention provides improved hydraulic systems wherein said phosphates are employed as the operative fluids. Such systems comprise a displaceable member contacted by said fluid, as shown in the schematic diagram of FIG- URE 1 of the drawing. Here, a displacing force is applied to piston 1 and transmitted through the fluid 2 contained in cylinder 3 whence it travels through line 4 into cylinder 5 where it acts on the displaceable member 6. In such a system, actuation of a moveable member by the presently provided fluid gives performance characteristics which are outstanding because of the physical properties of the fluid. While hydraulic systems will contain elements such as pumps, valves, cylinders and pistons, the

eflicacy of the system necessarily depends upon the fluid, since the fluid must be one which can withstand pressure and remain fluid under the conditions of use. FIGURE 2. of the drawings is a schematic diagram which well illustrates the indispensable role of the fluid in cooperation with other components of a hydraulic system. Here the fluid is stored in reservoir 21, and is pumped therefrom by means of pump 22 and through the directional control valve 23 into either end of cylinder 24, where it acts on piston 25 connected by shaft 26 to a motor (not shown) or other device which converts the hydraulic pressure applied to piston 25 into mechanical energy. Action of the fluid on piston 25 displaces the piston until it reaches the end of its travel. The piston may be caused to travel in either direction by adjustment of the directional valve 23. Valve 23 provides for return of the fluid from the opposite side of the piston, back to reservoir 21. Relief valve 27 is provided to maintain a constant hydraulic pressure within the system When a predetermined pressure is reached, the fluid will flow back to reservoir 21 by functioning of said relief valve.

Owing to their very good fire-retardant properties, the

presently provided phosphates are practicularly useful in hydraulic pressure devices that are employed under conditions wherein any leak or break in the hydraulic system could provide great danger from fire. The low pour points of the fluids permit fabrication of pressure devices which are destined for use in cold climates, and their very good vapor pressure characteristics and stability to heat allows use of the same devices in hot environments. The viscosity characteristics and ASTM slopes of the fluids make them of great utility for the transmission of power in a hydraulic system having a pump therein which supplies power for the system, e.g., in a fluid motor comprising a constantor variable-discharge piston pump which is caused to rotate by the pressure of the hydraulic fluid of the system. The present fluid likewise serves to lubricate moving parts of such hydraulic systems.

For use in a conventional automatic transmission, the presently provided hydraulic fluid is contained in the outer casing of the transmission device, which casing is attached to the usual engine crankshaft and flywheel and rotates therewith. Within the fluid is a coupling comprising an impeller connected to said casing and a turbine which is connected to the drive shaft of the vehicle. The turbine is driven by the motion of the fluid in response to the rotation of the impeller, as the casing to which the impeller is attached is actuated by the crankshaft and flywheel.

The present phosphates are particularly suited for use as the operative fluids in hydraulic braking devices owing to their very good vapor pressure characteristics. Under severe operating conditions heat build-up within the brake system is frequently encountered. Unless the fluid remains liquid at the high temperatures thus developed, the hydraulic brake system becomes inoperable since the vaporized fluid becomes compressible. Although much effort has been expended at providing high boiling hydraulic brake fluids, generally materials which are high boiling congeal at low temperatures.

The presently provided fluids are generally innocuous to the organic coatings which are conventionally used on metals. The fluids possess good hydrolytic stability.

The present phosphates are useful as the hydraulic fluids of hydraulic machines, generally, e.g., lifts, hoists, jacks, lock-gates, presses, etc.

The invention is further illustrated by, but not limited to, the following examples.

Example 1 m-Trifluoromethylphenyl phosphorodichloridate and bis(m-trifluoromethylphenyl) phosphorochloridate were prepared as follows: A mixture consisting of g. of crude m-trifluoromethylphenyl phosphorodichloridate boiling below C./l7 mm., which had been obtained by refluxing phosphoryl chloride with m-trifiuoromethyl phenol and distilling the reaction product, 539 g. (3.5 moles) of phosphoryl chloride and 1000 g. (6.18 moles) of m-trifluoromethylphenol, Was heated to reflux within a period of 20 hours, at the end of which time the temperature was 230 C. Distillation of the resulting reaction mixture gave 389.5 g. of the substantially pure m trifluoromethylphenyl phosphorodichloridate, B.P. 125-30 C./20 mm. and 814.2 g. of bis(m-trifluoromethylphenyl) phosphorochloridate, B.P. 195 C./ 20 mm.

To a mixture consisting of 17.8 g. (0.25 mole) of hy dracrylonitrile in 22.9 g. (0.29 mole) of pyridine there was added, dropwise over a period of 75 minutes, 101.1 g. (0.25 mole) of the bis(m-perfluorornethylphenyl) phosphorochloridate prepared above. The whole was then stirred for 2 hours at 65-75 C. and then allowed to cool to ambient temperature. After washing with dilute hydrochloric acid and with water to neutral, the organic phase was dried over magnesium sulfate and filtered. The filtrate Was evacuated to remove low-boiling volatiles and then distilled to remove material boiling up to 110 C./ 0.25 mm. The residue was filtered several times through clay and carbon black to give 83.5 g. (79.4% theoretical yield) of the substantially pure bis(m-perfluoromethylphenyl) 2-cyanoethyl phosphate, 11 1.4705.

The compound was found to have a pour point of minus 10 F., and the following kinematic viscosities were determined at the temperatures shown below:

Temp., F Centistokes 25 4291 100 74.27 210 6.49

To a mixture of 43.7 g. (0.66 mole) of hydracrylonitrile in 54.5 g. (0.69 mole) of dry pyridine there was added, dropwise over a 70 minute period, 82.6 g. (0.33 mole) of m-perfluoromethylphenyl phosphorodichloridate, B.P. 125-30" C./20 mm. which was prepared in Example 1. The whole was heated for 2 hours at 70- 80 C. After cooling to ambient, it was washed several times with dilute hydrochloric acid and several times With water, and the resulting organic phase was dried over magnesium sulfate and filtered, Vacuum treatment of the filtrate to a pot temperature of 120 C. removed any remaining by-product hydrochloride and unreacted material residue was successively filtered through clay, carbon black, and alumina to give the substantially pure bis(Z-cyanoethyl) m-perfluoromethylphenyl phosphate, n 1.4640, which analyzed as follows:

Calcd for C H N PF percent: C, 44.83; H, 3.47; F, 16.36. Found, percent: C, 44.58; H, 3.36; F, 16.13.

The phosphate was found to have a pour point of minus 15 F. and the following kinematic viscosities were determined at the temperatures shown below:

Temp., F.: Centistokes 25 33 67 100 76.01 210 7.1

draulic systems and methods may be a mixture of said phosphates, say, a mixture of isomeric bis(trifluoromethylphenyl) 2-cyanoethyl phosphates or a mixture of a bis(perfluoromethylphenyl) cyanoalkyl phosphate and a bis(cyanoalkyl) perfluoromethylphenyl phosphate. In some instances it will be found that compounds having the perfluoromethyl radical in the mand/or o-positions on the phenyl nucleus possess better fluidity than do the para-substituted compounds. Hence, the choice of compound may depend upon the environment in which the hydraulic pressure device is to be employed. The presently provided cyanoalkyl perfluoromethylphenyl phosphates may also be mixed with known hydraulic fluids, e.g., the trialkyl phosphates or the dialkyl arylphosphonates or the aromatic polyethers, so long as the properties of the resulting mixture meet the specifications required of a hydraulic fluid for the intended use. Obviously, if the contemplated use places no limitation on such factors as either lowor high-temperature behavior or paint compatibility; or if no fire-hazard exists, the present compounds may be used in any proportion. However, if one or more of these factors is important, then care should be observed in preventing an undesired extent of dilution. Generally, at least a major component of the mixture should be a cyanoalkyl perfluoromethyl phosphate.

Also, the usual fluid additives, e.g., corrosion inhibitors, antioxidants, viscosity-index improvers, etc., may be added to the present phosphates, although for most purposes it will be found that such additives can be dispensed with.

It is to be understood that although the invention has been described with specific reference to particular embodiments thereof, it is not to be so limited since changes and alterations therein may be made which are within the full intended scope of this invention as defined by the appended claims.

What we claim is:

1. The compound of the formula wherein each of m and n is 1 or 2 and the sum of m+n is 3 and alk denotes a bivalent alkylene radical of from 2 to 4 carbon atoms.

2. The compound of the formula wherein alk denotes a bivalent alkylene radical of from 2 to 4 carbon atoms.

3. The compound of the formula References Cited UNITED STATES PATENTS 2,957,018 lO/l960 Baker 260-940 2,960,525 11/1960 Dorken et al. 260940 2,965,533 12/1960 Whetstone 260-940 X CHARLES B. PARKER, Primary Examiner. BERNARD BILLIAN, Assistant Examiner. 

1. THE COMPOUND OF THE FORMULA 